Full-duplex wireless communication may be achieved exploiting the degrees of freedom available in time, frequency or other suitable domains. The two most prevalent duplexing schemes used in wireless communication systems are Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD). In FDD, the downlink (DL) and uplink (UL) transmissions are separated in frequency domain. In TDD, the DL and UL transmissions are separated in time domain.
TDD and FDD have their own disadvantages. For example, in 3G (e.g. WCDMA) or 4G (e.g. LTE) systems in which time-varying asymmetrical traffic of data services is overwhelming, FDD has a lower flexibility in adjusting UL/DL resource allocation for a better overall spectrum efficiency than TDD. Despite the high frequency efficiency gained by flexibly allocating time resource to UL/DL, TDD systems suffer from base station to base station interference due to possible radio propagation delay greater than the guard time of DL/UL switching or inaccurate synchronization.
The use of other independent dimensions to achieve duplexing has become attractive. Space Division Duplexing (SDD) has been proposed to exploit the degrees of freedom in space domain. However, due to the open radio propagation, allocating the same time and frequency resources for DL and UL transmission will cause serious interference. Some interference management methods have been proposed in the prior art. For example, it is discussed in WO2008/008013A1 a method for reducing the interference in an UL cell from nearby DL transmissions. However, the method is aimed to reduce temporary interference occurring in so-called “mixed mode or non-synchronized TDD” scenario in which one cell may receive interference from another nearby cell when the nearby cell temporally adapt the UL time slots to DL time slots. It is not sufficient to manage or reduce the significant and constant interference occurring in a SDD scenario.